Virgin Media is the most-complained about broadband, landline phone and pay-TV service in the UK.
The company attracted 32 complaints per 100,000 broadband customers between July and September 2023, regulator Ofcom said.
For pay monthly mobile services, O2, which is part of the same group as Virgin, attracted the most gripes.
Virgin Media O2 admitted the figures fell short of its expectations but said customer service was its priority.
Alongside Virgin Media, NOW Broadband and TalkTalk received higher-than-average numbers of complaints for their landline services, while NOW Broadband also received higher-than-average complaints about broadband.
Sky was the best-performing firm when it came to broadband, with only five complaints per 100,000 customers.
Fergal Farragher, Ofcom's consumer protection director, said there had been an overall "slight increase in complaints" compared with the previous quarter.
"Providers must continue to focus on improving customer service," he said.
Ofcom said a factor in Virgin Media's complaints figures was the regulator's announcement in July 2023 that it was launching an investigation into customers' difficulties cancelling contracts with the firm, and how it handled complaints.
"As well as engaging fully with Ofcom's ongoing investigation, we are investing in every area of our business to give our customers the best possible experience, with a real focus on resolving any issues at the first time of getting in touch and making it easier for them to get support when they need it," a Virgin Media O2 spokesperson said.
"Our number one priority is to provide an excellent service to our customers, and we accept that the rise in complaints in the third quarter falls far short of our expectations.
With pay monthly mobile phone services, the data showed six complaints per 100,000 customers for O2, compared with two for the best performing providers, Sky and EE.
Ofcom said that Sky continued to be the provider that attracted the fewest or joint fewest complaints per 100,000 subscribers across all four services.